As I've said multiple times. If Jesus was simply claiming to be alive when Abraham was, the correct grammar would be, 'before Abraham was, I was'. Saying 'before Abraham was, I am', would be incorrect grammar. Either it was incorrect grammar or it was a quote. They are the two options.
A Grammar of New Testament Greek, by J. H. Moulton, Vol. III (by Nigel Turner), p. 62, Edinburgh, 1963, comments specifically on this meaning at John 8:58:
"The present [tense] which indicates the
continuance of an action during the past
and up to the moment of speaking is virtually the same as perfective, the only difference being that the action is conceived of as
still in progress.... It is frequent in the NT: Lk 2:48, 13:7... John 5:6, 8:58 (eimi), 14:9 ... 15:27" - T and T Clark, 1963.
G. B. Winer ("
the great Greek grammarian of the 19th century" - Wallace) also tells us:
"Sometimes the Present includes also a past tense (mdv. 108), viz. when the verb expresses a state which
commenced at an earlier period but
still continues, - a state in its duration as, Jno. xv. 27 [Jn.15:27]..., viii. 58 [Jn 8:58]." -
A Grammar of the Idiom of the New Testament, Andover, 1897, p. 267.
Blass and Debrunner also list the following as NT instances of present tense verbs indicating the
duration of an act up to and including the present: Lk 13:7; 15:29;
Jn 8:58 (eimi)[12] 15:27
(este); 2 Cor. 12:19. - p. 168 (#322),
A Greek Grammar of the New Testament and Other Early Christian Literature, University of Chicago Press, 1961.
Also see Brooks and Winbery’s
Syntax of New Testament Greek, pp. 84-85, “Durative Present,” University Press of America, 1979.
Trinitarian A. T. Robertson also agrees with this understanding of the Greek present tense. He calls it "
The Progressive Present" and tells us that such a present tense verb often
"has to be translated into English by a sort of 'progressive
perfect' ('
have been')..." - p. 879,
A Grammar of the Greek New Testament in the Light of Historical Research.
Even
A Manual Grammar of the Greek New Testament by trinitarians Dana and Mantey confirms this understanding:
"b. The present [tense] approaches its kindred tense, the
perfect, when used to denote the
continuation of
existing results [D&M's emphasis in italics]. Here it refers to a fact which has
come to be in the past, but is emphasized as a present reality, as we say, '
I learn that you have moved' (that is, information has come to me in the past which I now possess). ....
"To say that this use is 'present for perfect' (Gildersleeve:
Syntax, p. 87) is not accurately representing the case. It does approach quite closely the significance of the
perfect [tense], but stresses the
continuance [D and M's emphasis] of results through present time which the perfect [tense] would not do, for the perfect stresses existence of results but
not their continuance. [The 'perfect indefinite tense' in English, however, as we have seen, does allow for such an understanding of continuance - RDB.] To say [
manthano auton elthein], 'I learn that he has gone,' has a force which is approximated only by ... 'I
have learned that he has gone'.
"c. Sometimes the
progressive present [tense] is retroactive in its application, denoting that which has
begun in the past and
continues into the present. For the want of a better name, we may call it the
present of duration. This use is generally associated with an adverb of time [as 'from the beginning' in Jn 15:27 and 'before Abraham came into existence' in John 8:58 which both act as 'adverbs of time' - RDB], and may best be rendered by the English
perfect. [Examples of this usage as given by Dana and Mantey are Jn. 15:27 (literally in the NT Greek: 'from beginning with me you are' and usually rendered into English as: 'you
have been with me from the beginning' -
RSV); Lk. 13:7; 2 Cor. 12:9 - RDB]." - pp. 182, 183, The Macmillan Company, 30th printing, 1965. [material in brackets has been added by me.]
Another NT scholar who verifies this is Kenneth L. McKay.
McKay said in his book,
A New Syntax of the Verb in New Testament Greek, An Aspectual Approach:
"Tense...4.2.4. Extension from Past. When used with an expression of either past time or extent of time with past implications (but not in past narrative, for which see 4.2.5), the present tense signals an activity
begun in the past and continuing to the present time: Luke 13:7...Lu 15:29....
Jn 14:9 [
Tosouton chronon meth humon eimi]..have I been with you so long...? ; Ac 27:33...
Jn 8:58 [prin Abraam ego eimi], I have been in existence since before Abraham was born...."
Perhaps even more surprising is this admission by hyper-trinitarian NT Greek scholar, Daniel B. Wallace:
A. Extending-from-Past Present (Present of Past Action Still in Progress)
1. Definition
The present tense may be used to describe an action which, begun in the past, continues in the present. ....
.... It is different from the progressive present in that it reaches back in time and usually has some sort of temporal indicator, such as
an adverbial phrase [such as 'before Abraham came into existence'], to show this past-referring element. Depending on how tightly one defines this category, it is either relatively rare or fairly common.
2. Key to Identification
The key to this usage is normally to translate the present as an
English present perfect. [And the presence of a 'temporal indicator, such as an adverbial phrase, to show this past-referring element.'] - pp. 519-520,
Greek Grammar Beyond the Basics, Zondervan, 1996.[13] [As in all other cases, bracketed material and emphasis are added by me.]